scholarly journals A theoretical model for predicting the behaviour of BTEX in the unsaturated zone and groundwater (Bahía Blanca, Argentina).

2021 ◽  
Author(s):  
Victoria Zanello ◽  
Leonardo Ezequiel Scherger ◽  
Micaela Carbajo Castoldi ◽  
Claudio Lexow
Keyword(s):  
Mathematical Model ◽  
Theoretical Model ◽  
Urban Areas ◽  
Unsaturated Zone ◽  
Chemical Properties ◽  
Main Process ◽  
Gas Stations ◽  
The World ◽  
Benzene Toluene ◽  
Volatile Phase

Abstract Gas stations are one of the most important sources of soil and groundwater contamination in urban areas around the world. In this work, a mathematical model was applied to assess the risk of the physical media contamination. The model is based on the chemical properties of fuels and site-specific hydrological properties. The group of hydrocarbons selected were the monoaromatic: benzene, toluene, ethylbenzene and xylene (BTEX). The mathematical model was used to evaluate the behaviour of each compound in each partitioning phase (dissolved, volatile, solid and non-aqueous liquid phase). Furthermore, mass flux of BTEX reaching groundwater was calculated according to steady flow under two different conditions: (1) considering only sorption and volatilization, and (2) adding biodegradation. In all cases, the total mass of BTEX leachate was greater when biodegradation was not considered. In areas with unsaturated zone thickness greater than two meters, sorption is the main process affecting BTEX transport. Otherwise, when water table is placed at shallower depths, contaminants are predominately dissolved. In all cases, the lowest proportion of BTEX were in the volatile phase. The model presented in this work proved to be an interesting tool to evaluate the behaviour of BTEX in soil and groundwater and its applicability being directly related to environmental and urban management of pollution from gas stations. The methodology applied in this work could be extrapolated to any site of the world with the same problematic. Particularly, the theoretical model allowed to defined zones with high and low risk of contamination in Bahia Blanca, Argentina.

From globalization to post-globalization: enclaves of augmented modernity and prospects of social development

2019 ◽  
pp. 12-18 ◽  
Author(s):  
Dmitry V. Ivanov
Keyword(s):  
Quality Of Life ◽  
Theoretical Model ◽  
Social Development ◽  
Urban Areas ◽  
Social Life ◽  
Standard Of Living ◽  
The Core ◽  
The World ◽  
Social Divide

The article presents an attempt to reconceptualize social development and to measure its level for societies facing the post-globalization as globalizing networks and flows paradoxically are localized in super-urban areas. The economic and social divide between the group of the largest cities and the rest of the world supports the idea that globalization has resulted not in the ‘world society’ or ‘worldwide sociality’ but rather in networked enclaves of globality where people experience borderless, multicultural, and mobile social life in the regime of augmented modernity. In the post-globalization age, the ‘core’ of socioeconomic order is dispersed into networks of enclaves of augmented modernity contrasting with exhausted modernity outside them. The nations’ prospects of social development depend on number, size, and influence of cosmopolitan super-urban areas attracting and generating transnational material, human, and symbolic flows. The super-urbanization index is elaborated to measure nations’ prospects under post-globalization conditions. Traditional indices of standard of living and quality of life have to be augmented in the new theoretical model and system of empirical indicators of social development under post-globalization conditions.

COMPARATIVE METHOD IN CONSTITUTIONAL LAW: BETWEEN PRESUMPTIONS OF SIMILARITIES AND DIFFERENCES

2019 ◽  
Vol 14 (5) ◽  
pp. 84-113
Author(s):  
ALEXANDRA A. TROITSKAYA
Keyword(s):  
Political Philosophy ◽  
Theoretical Model ◽  
Constitutional Law ◽  
Comparative Method ◽  
Comparative Law ◽  
Middle Level ◽  
Legal Research ◽  
Universal Principles ◽  
The World ◽  
Similarities And Differences

The two main approaches to the use of the comparative method in legal research, functional and cultural, have some "predetermined" considerations regarding the results that will (or should) be discovered by comparing various legal phenomena — should the emphasis be on similarities or differences between these phenomena. These considerations are based on the vision of, respectively, the universal or pluralistic nature of law of various societies, and in fact they are able to correct substantially the process of cognition of legal phenomena using the comparative method, adjusting it to the desired result. In the case of similarities, we can talk about artificially narrowing the circle of countries under investigation. In the case of differences, the isolation of systems and the uniqueness of their cultural characteristics are unreasonably exaggerated. The alternative assumptions presented in the theory of comparative law regarding the existence of universal principles of law or the fundamental uniqueness of each legal system require a critical rethinking of constitutional provisions and practice in comparative studies. The use of the comparative method in constitutional law is not reducible to the implementation of the ideas of political philosophy, and objective conclusions should not be replaced by predetermined normative guidelines. The similarities and differences revealed by the researcher of constitutional ideas, norms and practices can be considered as a result of comparison of independent value.Constitutional law is associated with a variety of substantial constructs existing in the world, not excluding, however, their intercommunication. Understanding these constructions requires attention to both the similarities and the differences in specific legal orders (as well as the reasons for their functioning in this, and not another form). The use of the comparative method in the absence of striving for predetermined results is simultaneously aimed at understanding the laws of development of constitutional institutions and maintaining the horizon of their diversity as an important component of this development. Each time, the researcher should distance himself from his prejudices regarding the similarities or differences between the institutes under study, rechecking whether the obtained results are really the results of applying the comparative method, and not the initial constructions.The logic of a comparative study corresponds to the construction of theories of "middle level", aimed at forming the theoretical model of a particular legal in-stitution, taking into account the practice of implementing this institution in specific states. The focus on middle-level theories within the framework of the comparative method allows one to go beyond the description of single systems, formulate conclusions at the level of generalization that ensure the comparability of the studied objects, and at the same time maintain an understanding of the diversity of constitutional models.

Network analysis models – the secret for success

2004 ◽  
Vol 4 (5-6) ◽  
pp. 383-388
Author(s):  
D.M. Rogers
Keyword(s):  
Mathematical Model ◽  
Field Data ◽  
Essential Element ◽  
Distribution Networks ◽  
Automatic Calibration ◽  
Supply And Distribution ◽  
The World ◽  
Optimum Approach ◽  
Analysis Models

Water is a fundamental necessity of life. Yet water supply and distribution networks the world over are old and lacking in adequate maintenance. Consequently they often leak as much water as they deliver and provide an unacceptable quality of service to the customer. In certain parts of the world, water is available only for a few hours of the day. The solution is to build a mathematical model to simulate the operation of the real network in all of its key elements and apply it to optimise its operation. To be of value, the results of the model must be compared with field data. This process is known as calibration and is an essential element in the construction of an accurate model. This paper outlines the optimum approach to building and calibrating a mathematical model and how it can be applied to automatic calibration systems.

Urban Transport

2018 ◽  
Author(s):  
José van
Keyword(s):  
Urban Areas ◽  
Urban Transport ◽  
Transport Sector ◽  
Public And Private ◽  
Transport Services ◽  
Ride Sharing ◽  
The World ◽  
Private And Public ◽  
Selection Mechanisms

Platformization affects the entire urban transport sector, effectively blurring the division between private and public transport modalities; existing public–private arrangements have started to shift as a result. This chapter analyzes and discusses the emergence of a platform ecology for urban transport, focusing on two central public values: the quality of urban transport and the organization of labor and workers’ rights. Using the prism of platform mechanisms, it analyzes how the sector of urban transport is changing societal organization in various urban areas across the world. Datafication has allowed numerous new actors to offer their bike-, car-, or ride-sharing services online; selection mechanisms help match old and new complementors with passengers. Similarly, new connective platforms are emerging, most prominently transport network companies such as Uber and Lyft that offer public and private transport options, as well as new platforms offering integrated transport services, often referred to as “mobility as a service.”

scholarly journals Modelling the impact of delaying vaccination against SARS-CoV-2 assuming unlimited vaccine supply

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Marcos Amaku ◽  
Dimas Tadeu Covas ◽  
Francisco Antonio Bezerra Coutinho ◽  
Raymundo Soares Azevedo ◽  
Eduardo Massad
Keyword(s):  
Mathematical Model ◽  
Vaccination Campaign ◽  
Vaccination Rate ◽  
Sao Paulo ◽  
The State ◽  
São Paulo ◽  
Health Authorities ◽  
The World ◽  
The Moment ◽  
The Impact

Abstract Background At the moment we have more than 177 million cases and 3.8 million deaths (as of June 2021) around the world and vaccination represents the only hope to control the pandemic. Imperfections in planning vaccine acquisition and difficulties in implementing distribution among the population, however, have hampered the control of the virus so far. Methods We propose a new mathematical model to estimate the impact of vaccination delay against the 2019 coronavirus disease (COVID-19) on the number of cases and deaths due to the disease in Brazil. We apply the model to Brazil as a whole and to the State of Sao Paulo, the most affected by COVID-19 in Brazil. We simulated the model for the populations of the State of Sao Paulo and Brazil as a whole, varying the scenarios related to vaccine efficacy and compliance from the populations. Results The model projects that, in the absence of vaccination, almost 170 thousand deaths and more than 350 thousand deaths will occur by the end of 2021 for Sao Paulo and Brazil, respectively. If in contrast, Sao Paulo and Brazil had enough vaccine supply and so started a vaccination campaign in January with the maximum vaccination rate, compliance and efficacy, they could have averted more than 112 thousand deaths and 127 thousand deaths, respectively. In addition, for each month of delay the number of deaths increases monotonically in a logarithmic fashion, for both the State of Sao Paulo and Brazil as a whole. Conclusions Our model shows that the current delay in the vaccination schedules that is observed in many countries has serious consequences in terms of mortality by the disease and should serve as an alert to health authorities to speed the process up such that the highest number of people to be immunized is reached in the shortest period of time.

scholarly journals High Diversity in Urban Areas: How Comprehensive Sampling Reveals High Ant Species Richness within One of the Most Urbanized Regions of the World

Diversity ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 358
Author(s):  
François Brassard ◽  
Chi-Man Leong ◽  
Hoi-Hou Chan ◽  
Benoit Guénard
Keyword(s):  
Exotic Species ◽  
Urban Areas ◽  
Urban Landscapes ◽  
Dual Roles ◽  
Ant Communities ◽  
Continuous Increase ◽  
Tropical Regions ◽  
The World ◽  
Ant Diversity ◽  
The Vertical Distribution

The continuous increase in urbanization has been perceived as a major threat for biodiversity, particularly within tropical regions. Urban areas, however, may still provide opportunities for conservation. In this study focused on Macao (China), one of the most densely populated regions on Earth, we used a comprehensive approach, targeting all the vertical strata inhabited by ants, to document the diversity of both native and exotic species, and to produce an updated checklist. We then compared these results with 112 studies on urban ants to illustrate the dual roles of cities in sustaining ant diversity and supporting the spread of exotic species. Our study provides the first assessment on the vertical distribution of urban ant communities, allowing the detection of 55 new records in Macao, for a total of 155 ant species (11.5% being exotic); one of the highest species counts reported for a city globally. Overall, our results contrast with the dominant paradigm that urban landscapes have limited conservation value but supports the hypothesis that cities act as gateways for exotic species. Ultimately, we argue for a more comprehensive understanding of ants within cities around the world to understand native and exotic patterns of diversity.

scholarly journals Seasonal variation and spatial distribution of carbonaceous aerosols in Taiwan

2010 ◽  
Vol 10 (19) ◽  
pp. 9563-9578 ◽  
Author(s):  
C. C.-K. Chou ◽  
C. T. Lee ◽  
M. T. Cheng ◽  
C. S. Yuan ◽  
S. J. Chen ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Rural Areas ◽  
Urban Areas ◽  
Air Pollutants ◽  
Chemical Properties ◽  
Anthropogenic Sources ◽  
Carbonaceous Aerosols ◽  
Urban Rural ◽  
Southern Taiwan ◽  
Northern Taiwan

Abstract. To investigate the physico-chemical properties of aerosols in Taiwan, an observation network was initiated in 2003. In this work, the measurements of the mass concentration and carbonaceous composition of PM10 and PM2.5 are presented. Analysis on the data collected in the first 5-years, from 2003 to 2007, showed that there was a very strong contrast in the aerosol concentration and composition between the rural and the urban/suburban stations. The five-year means of EC at the respective stations ranged from 0.9±0.04 to 4.2±0.1 μgC m−3. In rural areas, EC accounted for 2–3% of PM10 and 3–5% of PM2.5 mass loadings, comparing to 4–6% of PM10 and 4–8% of PM2.5 in the urban areas. It was found that the spatial distribution of EC was consistent with CO and NOx across the network stations, suggesting that the levels of EC over Taiwan were dominated by local sources. The measured OC was split into POC and SOC counterparts following the EC tracer method. Five-year means of POC ranged from 1.8±0.1 to 9.7±0.2 μgC m−3 among the stations. It was estimated that the POM contributed 5–17% of PM10 and 7–18% of PM2.5 in Taiwan. On the other hand, the five-year means of SOC ranged from 1.5±0.1 to 3.8±.3 μgC m−3. The mass fractions of SOM were estimated to be 9–19% in PM10 and 14–22% in PM2.5. The results showed that the SOC did not exhibit significant urban-rural contrast as did the POC and EC. A significant cross-station correlation between SOC and total oxidant was observed, which means the spatial distribution of SOC in Taiwan was dominated by the oxidant mixing ratio. Besides, correlation was also found between SOC and particulate nitrate, implying that the precursors of SOA were mainly from local anthropogenic sources. In addition to the spatial distribution, the carbonaceous aerosols also exhibited distinct seasonality. In northern Taiwan, the concentrations of all the three carbonaceous components (EC, POC, and SOC) reached their respective minima in the fall season. POC and EC increased drastically in winter and peaked in spring, whereas the SOC was characterized by a bimodal pattern with the maximal concentration in winter and a second mode in summertime. In southern Taiwan, minimal levels of POC and EC occurred consistently in summer and the maxima were observed in winter, whereas the SOC peaked in summer and declined in wintertime. The discrepancies in the seasonality of carbonaceous aerosols between northern and southern Taiwan were most likely caused by the seasonal meteorological settings that dominated the dispersion of air pollutants. Moreover, it was inferred that the Asian pollution outbreaks could have shifted the seasonal maxima of air pollutants from winter to spring in the northern Taiwan, and that the increases in biogenic SOA precursors and the enhancement in SOA yield were responsible for the elevated SOC concentrations in summer.

Beyond studentification in United States College Towns: Neighborhood change in the knowledge nodes, 1980–2010

2017 ◽  
Vol 49 (6) ◽  
pp. 1341-1360 ◽  
Author(s):  
Nathan S Foote
Keyword(s):  
United States ◽  
Middle Class ◽  
Knowledge Economy ◽  
Urban Areas ◽  
Global Economy ◽  
Neighborhood Change ◽  
Global Knowledge ◽  
College Towns ◽  
The World ◽  
Social Geographies

With the rise of the cognitive-cultural (or knowledge) economy, urban areas around the world have experienced significant changes in their social geographies. Studentification is one such change that has occurred in cities hosting major universities around the world. This study extends the analysis of social change to vital knowledge nodes in the networked global economy: United States college towns. K-means cluster analysis is used to identify neighborhood types in ten cities with major research universities across four Census years: 1980, 1990, 2000, and 2010. Temporal and spatial analyses are then conducted to determine how these knowledge nodes have changed with the decline of the industrial economy and the rise of the knowledge economy. The analysis indicates the presence of six neighborhood types in these college towns: Middle Class, Minority-Concentrated, Stability, Elite, Mix/Renter, and Student. Over the course of the study period, the number of Elite neighborhoods increased considerably, while the number of Middle Class neighborhoods plummeted. The number of Mix/Renter neighborhoods also increased. Spatially, Student and Minority-Concentrated neighborhoods generally remained fairly clustered in the same areas across the study period. Elite neighborhoods spread across wider geographical areas over the course of the study period. These results are compared to previous studies on neighborhood change. The comparisons reveal that the knowledge nodes show some similar patterns to studentifying cities and to rapidly growing nodes in areas with ties to the global knowledge economy.

Reconceptualizing the Public Spaces of New Urban Areas in Hanoi: The End or the New of Public-Making?

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Minh-Tung Tran ◽  
◽  
Tien-Hau Phan ◽  
Ngoc-Huyen Chu ◽  
◽  
...  
Keyword(s):  
Public Space ◽  
Urban Areas ◽  
Public Spaces ◽  
The Public ◽  
Doi Moi ◽  
The World ◽  
Relationship Of ◽  
The Relationship ◽  
The City ◽  
Neighborhood Level

Public spaces are designed and managed in many different ways. In Hanoi, after the Doi moi policy in 1986, the transfer of the public spaces creation at the neighborhood-level to the private sector has prospered na-ture of public and added a large amount of public space for the city, directly impacting on citizen's daily life, creating a new trend, new concept of public spaces. This article looks forward to understanding the public spaces-making and operating in KDTMs (Khu Do Thi Moi - new urban areas) in Hanoi to answer the question of whether ‘socialization’/privatization of these public spaces will put an end to the urban public or the new means of public-making trend. Based on the comparison and literature review of studies in the world on public spaces privatization with domestic studies to see the differences in the Vietnamese context leading to differences in definitions and roles and the concept of public spaces in KDTMs of Hanoi. Through adducing and analyzing practical cases, the article also mentions the trends, the issues, the ways and the technologies of public-making and public-spaces-making in KDTMs of Hanoi. Win/loss and the relationship of the three most important influential actors in this process (municipality, KDTM owners, inhabitants/citizens) is also considered to reconceptualize the public spaces of KDTMs in Hanoi.

Mathematical modeling of fluid movement inside the eyeball during intravitreal injection

2021 ◽  
pp. 106-109
Author(s):  
D.V. Lipatov ◽  
◽  
S.A. Skladchikov ◽  
N.P. Savenkova ◽  
V.V. Novoderezkin ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Residence Time ◽  
Complex Structure ◽  
Posterior Vitreous Detachment ◽  
Vitreous Body ◽  
Complete Removal ◽  
Intravitreal Injections ◽  
The World

Background. The avalanche-like growth of intravitreal injections in the world has significantly increased interest in the hemodynamics of the processes that occur in the eye when a drug is injected into the vitreous cavity. Every year, the number of intravitreally used drugs and promising areas in which they can be used is growing. This also applies to the creation of new combined medicines and the development of drugs with a long-term therapeutic effect. Aims. Create mathematical model of eyeball to evaluate the movement of the drug substance in it; to estimate the time of the drug's presence in the eye cavity before its complete removal, to characterize the ways of its removal from the eye cavity; to assess the significance of posterior vitreous detachment during the time when the drug is present in the eye cavity; to evaluate the effect on the hydrodynamics of the depth of drug administration. Results. When the drug is administered closer to the center of the eyeball, its residence time increases in comparison with the parietal administration. With a complete posterior detachment of the vitreous body, the time of finding the drug in the eye is prolonged compared to its absence. The obtained results of mathematical modeling of the movement of the drug administered intravitreally cannot be mechanically transferred to the human eye, due to the more complex structure of the latter. Key words: intravitreal injections, vitreous body, mathematic computing.

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